Deprecate Configuration::getProxyDir and setProxyDir

[GromNaN]

Q	A
Type	improvement
BC Break	no
Fixed issues	-

Summary

The proxy dir is not used when native lazy objects are used. Trigger the deprecation only when it's enabled.

[greg0ire]

This should be mentioned in the upgrade guide, and I think the annotations are not OK since the deprecation is conditional

[alcaeus]

This should be mentioned in the upgrade guide, and I think the annotations are not OK since the deprecation is conditional

I think the annotations are fine, since we'll be removing the methods along with all non-native proxies in 3.0.

[GromNaN]

This should be mentioned in the upgrade guide,

I added the upgrade instructions.

and I think the annotations are not OK since the deprecation is conditional

Calling this methods is actually deprecated. I could also mark them as @internal because we still need to use them internally. But we are going to remove them in 3.0. #2914

I don't want to have to keep this methods in 3.0 because we can't deprecate them in 2.x.

[greg0ire]

Calling this methods is actually deprecated.

Oh OK great then 👍